Overexpose on lowest iso?

[jr4089]

I have a problem, today I went out to go and shoot in daylight, my iso was set at 100, aperture in f8, and my shutter speed in 50 shooting 24p. This whole time my camera seem overexpose nothing my white and just a little bit of the person I am shooting. Does dslr's do this?

[antman]

I have a problem, today I went out to go and shoot in daylight, my iso was set at 100, aperture in f8, and my shutter speed in 50 shooting 24p. This whole time my camera seem overexpose nothing my white and just a little bit of the person I am shooting. Does dslr's do this?

Dslr's have a larger sensor, which brings in more light than a 1/3rd sensor. Thats why their so much better in low light.The only way to fix your exposure problems is to either get some Nd filters, raise your shutter speed, or close your iris on the lens. It's not advisable to close your iris past f-8, or you will start to see issues with the lens. (barrell.-distortion, softer image, chromatic aberation) Each lens has a sweet spot, usually around f4-8. Anything before or after that, you start to see a softer image.

If your on a controlled set, then you can control light with flags, cutters, gobo's. I like to use a butterfly overhead if I'm shooting outside talent.

[Bif]

The easiest solution is to carry 2 ND filters. .6 (2 stop reduction in light coming through the lens) and .9 (3 stop reduction), in extreme cases like needing to use f2.8 to f1.8 in daylight (not direct sunlight) the two filters can be "stacked" giving you a 5 stop reduction.

Be careful of doing this with cheap ND filters because you can get a color shift, Tiffen is lowest quality brand I would try, that's what I have and sometimes I see a very slight magenta shift with those when I "stack" them (correctable in post with many NLE's). Most of the time it's not noticeable enough to be a problem.

If using a DSLR you most definitely should be using a viewfinder loupe that excludes extraneous light. Without such there is almost no way you can see what is happening with your exposure. You have 3 ways of monitoring outdoor exposure with a DSLR; the meter indicator at the bottom of the screen (moving indicator should be somewhere close to the index mark), look and appearance of the image on the LCD screen if you have LCD brightness adjusted so you can see all steps on the greyscale bar on the LCD brightness adjust screen, and the histogram from either a very short test video or from a still image viewed in "play" mode (with the display set to show histogram).

Bruce Foreman

[cgbier]

Bif, how's about the good, old incident light meter?

[drapeama]

Be careful of doing this with cheap ND filters because you can get a color shift, Tiffen is lowest quality brand I would try, that's what I have and sometimes I see a very slight magenta shift with those when I "stack" them (correctable in post with many NLE's). Most of the time it's not noticeable enough to be a problem.

I've bought some from ebay user jiakgong for a ridiculous price and I never had any problem with them. Maybe I've just been lucky.

[Janke]

It's not advisable to close your iris past f-8, or you will start to see issues with the lens. (barrell.-distortion, softer image, chromatic aberation) Each lens has a sweet spot, usually around f4-8. Anything before or after that, you start to see a softer image.

Well, that's a truth with modification.

Distortion won't usually change when you stop down - it's there all the time. Also, chromatic aberration is there all the time.

What happens when you stop down is this:

Spherical aberration and field curvature, which soften the image at full aperture, get less noticeable. DOF grows. This makes for a sharper image.

However, if you stop down too far, diffraction starts to soften the image. It starts almost unnoticeably at maybe f8 or so, but in my opinion, doesn't become bothersome before f16, maybe even f22, when it can soften the image just as much as using the lens at full aperture.

I've done tests with all my 16 lenses (yeah, too many, I know... ) and none of them have been worse at f16 than fully open.

More often than not, the "sweet spot" of a lens is 2-3 steps stopped down from fully open, when you look at the center of the image. In the corners, zoom lenses improve a bit even after that. Then, diffraction kicks in, and you get a slight softness all over the frame.

[Bif]

Bif, how's about the good, old incident light meter?

Well, that's something from a bygone age for most, except for a few of us who remember how to use and interpret them. I still have a Sekonic (looks just like the older Norwood Director) I bought coming back from VietNam in Dec 1970. I drag it out every now and then but the meters in our Canon DSLRs are amazingly accurate (in most cases).

Bruce Foreman

[Janke]

the meters in our Canon DSLRs are amazingly accurate

Histograms rule!

But I still have and treasure my two meters, a Pentax 1° spotmeter*, and a Zeiss Ikon fully electronic one.

* Needs a special mercury battery, not available anymore. It does last for years and years, and I've got a spare in the fridge, in an airtight film can...